The present invention relates to methods for producing integrated circuit devices and more specifically to a shallow junction spin on glass (SOG) process.
Known methods for forming junctions between semiconductor materials involve a masking operation followed by an implant operation in which n-type and p-type impurities are implanted into a substrate, typically silicon. In such a process, the implant energy has to be reduced to produce shallow junctions.
This method suffers from the disadvantage that implanting produces defects which lie in the space charge region of the junction. The implanted impurity is brought to rest by an inelastic collision with silicon atoms in the crystal lattice, which damages the crystal lattice structure by knocking silicon atoms out of place. The crystal lattice structure must be epitaxially regrown by an activation anneal, which can be a rapid thermal process (RTP) cycle. However, the anneal process causes undesirable enhanced diffusion. The damage from implanting is not totally repairable. Defect sites having energies in the middle of the band gap remain and produce a conduction path which ultimately causes a leakage current to flow through the junction.
Therefore, it would be desirable to provide a process for forming shallow junctions which does not suffer from the disadvantages of implanting.